3b2011fd4f
When the IV is only used by the terminating condition (say IV-A) and the loop has a predictable back-edge count and we have another IV (say IV-B) that is an affine add recursion, we will be able to calculate the terminating value of IV-B in the loop pre-header. This patch adds attempts to replace IV-B as the new terminating condition and remove IV-A. It is safe to do so since IV-A is only used as the terminating condition. This transformation is suitable to be appended after LSR as it may optimize the loop into the situation mentioned above. The transformation can reduce number of IV-s in the loop by one. A cli option `lsr-term-fold` is added and default disabled. Reviewed By: mcberg2021, craig.topper Differential Revision: https://reviews.llvm.org/D132443
136 lines
5.6 KiB
LLVM
136 lines
5.6 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
|
|
; RUN: opt < %s -passes="loop-reduce" -S -lsr-term-fold | FileCheck %s
|
|
|
|
; There are 3 test cases here regarding the replacing the primary iv with
|
|
; other affine AddRec IV.
|
|
; 1. Loop with constant tripcount
|
|
; 2. Loop with runtime tripcount
|
|
; 3. The replacing AddRec IV is a complicated AddRec. This tests whether
|
|
; the fold terminating condition transformation is writing new terminating
|
|
; condition in the correct type.
|
|
|
|
target datalayout = "e-p:32:32:32-n32"
|
|
|
|
; This is equivalent to the following code, loop guard is removed.
|
|
; void const_tripcount(int *a) {
|
|
; for (int i = 21; i < 400; i++)
|
|
; a[i] = 1;
|
|
; }
|
|
define void @const_tripcount(ptr %a) {
|
|
; CHECK-LABEL: @const_tripcount(
|
|
; CHECK-NEXT: entry:
|
|
; CHECK-NEXT: [[UGLYGEP:%.*]] = getelementptr i8, ptr [[A:%.*]], i64 84
|
|
; CHECK-NEXT: [[UGLYGEP1:%.*]] = getelementptr i8, ptr [[A]], i32 1600
|
|
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
|
|
; CHECK: for.body:
|
|
; CHECK-NEXT: [[LSR_IV1:%.*]] = phi ptr [ [[UGLYGEP2:%.*]], [[FOR_BODY]] ], [ [[UGLYGEP]], [[ENTRY:%.*]] ]
|
|
; CHECK-NEXT: store i32 1, ptr [[LSR_IV1]], align 4
|
|
; CHECK-NEXT: [[UGLYGEP2]] = getelementptr i8, ptr [[LSR_IV1]], i64 4
|
|
; CHECK-NEXT: [[LSR_FOLD_TERM_COND_REPLACED_TERM_COND:%.*]] = icmp eq ptr [[UGLYGEP2]], [[UGLYGEP1]]
|
|
; CHECK-NEXT: br i1 [[LSR_FOLD_TERM_COND_REPLACED_TERM_COND]], label [[FOR_END:%.*]], label [[FOR_BODY]]
|
|
; CHECK: for.end:
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
entry:
|
|
%uglygep = getelementptr i8, ptr %a, i64 84
|
|
br label %for.body
|
|
|
|
for.body: ; preds = %for.body, %entry
|
|
%lsr.iv1 = phi ptr [ %uglygep2, %for.body ], [ %uglygep, %entry ]
|
|
%lsr.iv = phi i64 [ %lsr.iv.next, %for.body ], [ 379, %entry ]
|
|
store i32 1, ptr %lsr.iv1, align 4
|
|
%lsr.iv.next = add nsw i64 %lsr.iv, -1
|
|
%uglygep2 = getelementptr i8, ptr %lsr.iv1, i64 4
|
|
%exitcond.not = icmp eq i64 %lsr.iv.next, 0
|
|
br i1 %exitcond.not, label %for.end, label %for.body
|
|
|
|
for.end: ; preds = %for.body
|
|
ret void
|
|
}
|
|
|
|
; This is equivalent to the following code, loop guard is removed.
|
|
; void runtime_tripcount(int *a, int N) {
|
|
; for (int i = 21; i < N; i++)
|
|
; a[i] = 1;
|
|
; }
|
|
|
|
define void @runtime_tripcount(ptr %a, i32 %N) {
|
|
; CHECK-LABEL: @runtime_tripcount(
|
|
; CHECK-NEXT: entry:
|
|
; CHECK-NEXT: [[UGLYGEP:%.*]] = getelementptr i8, ptr [[A:%.*]], i32 84
|
|
; CHECK-NEXT: [[TMP0:%.*]] = shl i32 [[N:%.*]], 2
|
|
; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[TMP0]], 84
|
|
; CHECK-NEXT: [[UGLYGEP1:%.*]] = getelementptr i8, ptr [[A]], i32 [[TMP1]]
|
|
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
|
|
; CHECK: for.body:
|
|
; CHECK-NEXT: [[LSR_IV1:%.*]] = phi ptr [ [[UGLYGEP2:%.*]], [[FOR_BODY]] ], [ [[UGLYGEP]], [[ENTRY:%.*]] ]
|
|
; CHECK-NEXT: store i32 1, ptr [[LSR_IV1]], align 4
|
|
; CHECK-NEXT: [[UGLYGEP2]] = getelementptr i8, ptr [[LSR_IV1]], i64 4
|
|
; CHECK-NEXT: [[LSR_FOLD_TERM_COND_REPLACED_TERM_COND:%.*]] = icmp eq ptr [[UGLYGEP2]], [[UGLYGEP1]]
|
|
; CHECK-NEXT: br i1 [[LSR_FOLD_TERM_COND_REPLACED_TERM_COND]], label [[FOR_END:%.*]], label [[FOR_BODY]]
|
|
; CHECK: for.end:
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
entry:
|
|
%uglygep = getelementptr i8, ptr %a, i32 84
|
|
br label %for.body
|
|
|
|
for.body: ; preds = %for.body, %entry
|
|
%lsr.iv1 = phi ptr [ %uglygep2, %for.body ], [ %uglygep, %entry ]
|
|
%lsr.iv = phi i32 [ %lsr.iv.next, %for.body ], [ %N, %entry ]
|
|
store i32 1, ptr %lsr.iv1, align 4
|
|
%lsr.iv.next = add nsw i32 %lsr.iv, -1
|
|
%uglygep2 = getelementptr i8, ptr %lsr.iv1, i64 4
|
|
%exitcond.not = icmp eq i32 %lsr.iv.next, 0
|
|
br i1 %exitcond.not, label %for.end, label %for.body
|
|
|
|
for.end: ; preds = %for.body
|
|
ret void
|
|
}
|
|
|
|
; This is modified from IR of the following code, loop guard is removed.
|
|
; void foo(int*);
|
|
; void ptr_of_ptr_addrec(int **ptrptr, int length) {
|
|
; int **it = ptrptr;
|
|
; for (int i = length; i; i--) {
|
|
; foo(*it);
|
|
; it++;
|
|
; }
|
|
; }
|
|
define void @ptr_of_ptr_addrec(ptr %ptrptr, i32 %length) {
|
|
; CHECK-LABEL: @ptr_of_ptr_addrec(
|
|
; CHECK-NEXT: entry:
|
|
; CHECK-NEXT: [[START_PTRPTR:%.*]] = getelementptr ptr, ptr [[PTRPTR:%.*]]
|
|
; CHECK-NEXT: [[TMP0:%.*]] = shl i32 [[LENGTH:%.*]], 2
|
|
; CHECK-NEXT: [[UGLYGEP:%.*]] = getelementptr i8, ptr [[START_PTRPTR]], i32 [[TMP0]]
|
|
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
|
|
; CHECK: for.body:
|
|
; CHECK-NEXT: [[IT_04:%.*]] = phi ptr [ [[INCDEC_PTR:%.*]], [[FOR_BODY]] ], [ [[START_PTRPTR]], [[ENTRY:%.*]] ]
|
|
; CHECK-NEXT: [[TMP1:%.*]] = load ptr, ptr [[IT_04]], align 8
|
|
; CHECK-NEXT: tail call void @foo(ptr [[TMP1]])
|
|
; CHECK-NEXT: [[INCDEC_PTR]] = getelementptr inbounds ptr, ptr [[IT_04]], i64 1
|
|
; CHECK-NEXT: [[LSR_FOLD_TERM_COND_REPLACED_TERM_COND:%.*]] = icmp eq ptr [[INCDEC_PTR]], [[UGLYGEP]]
|
|
; CHECK-NEXT: br i1 [[LSR_FOLD_TERM_COND_REPLACED_TERM_COND]], label [[FOR_END:%.*]], label [[FOR_BODY]]
|
|
; CHECK: for.end:
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
entry:
|
|
%start.ptrptr = getelementptr inbounds ptr, ptr %ptrptr
|
|
br label %for.body
|
|
|
|
for.body: ; preds = %entry, %for.body
|
|
%i.05 = phi i32 [ %dec, %for.body ], [ %length, %entry ]
|
|
%it.04 = phi ptr [ %incdec.ptr, %for.body ], [ %start.ptrptr, %entry ]
|
|
%0 = load ptr, ptr %it.04, align 8
|
|
tail call void @foo(ptr %0)
|
|
%incdec.ptr = getelementptr inbounds ptr, ptr %it.04, i64 1
|
|
%dec = add nsw i32 %i.05, -1
|
|
%tobool.not = icmp eq i32 %dec, 0
|
|
br i1 %tobool.not, label %for.end, label %for.body
|
|
|
|
for.end: ; preds = %for.body
|
|
ret void
|
|
}
|
|
|
|
declare void @foo(ptr)
|